Law of Torts
Volenti Non Fit Injuria: Knowledge, Consent, and Why Mere Knowledge of a Risk Is Never Enough
To one who consents, no injury is done. The defence requires three things, and the burden of proving all three lies on the defendant: the plaintiff knew of the risk, he agreed to run it, and his agreement was free and voluntary. The second element is where nearly every argument is won or lost, because knowledge alone is never enough. Scienti non fit injuria is not the maxim, and a workman who knows a danger exists and protests about it has not consented to bear it. The defence is narrower still in employment, is excluded altogether in rescue cases, and in medical treatment operates as informed consent to what would otherwise be a battery.
The three essentials, why knowledge is not consent, and the four settings in which the defence is argued
1. The Three Essentials
1. Knowledge of the risk. The plaintiff must have known of the risk in its nature and extent, not merely that some danger existed somewhere.
2. Agreement to run it. He must have consented to bear the risk, expressly or by conduct. This is the element that knowledge does not supply.
3. A free and voluntary agreement. The consent must not have been obtained by fraud or compulsion, and must have been given by a person with capacity to give it.
4. The burden of proving all three is on the defendant, and it is a heavy one. The courts do not readily infer that a person agreed to bear a risk another created.
5. The consent must extend to the negligence complained of. Consent to the act does not by itself import consent to its negligent performance. A patient who consents to an operation does not consent to its being done carelessly.
2. Knowledge Is Not Consent
📖 Smith v. Charles Baker and Sons [1891] AC 325 Facts The plaintiff was employed to drill holes in a rock cutting. A crane worked overhead, swinging stones across the place where he was working, without any warning being given when a stone was passing. He knew of the practice and had complained about it. A stone fell from the crane and injured him. Held The employer was liable. The defence of volenti non fit injuria failed. Ratio Knowledge of a danger is not the same as consent to bear the risk of it. The maxim is volenti non fit injuria and not scienti non fit injuria. The question is not whether the plaintiff knew of the physical danger, but whether he freely agreed to undertake the legal risk and to absolve the employer from his duty. A workman who continues at his employment, having protested, does not by that fact consent to the employer's negligence. |
- The distinction is between the physical risk and the legal risk. A person may know perfectly well that a place is dangerous, and still be saying, in effect, that if he is injured by the defendant's carelessness he will sue.
- Protest is strong evidence against consent, though its absence does not establish consent.
- Continuing in the employment is not consent, because the choice between the risk and the loss of one's livelihood is not a free one.
3. Where the Consent Is Not Free
The vitiating factor | Why the defence fails |
Fraud | Where the true nature of the act is concealed, the consent is to something else. Consent to an examination obtained by concealing its real purpose is no consent to what was in fact done |
Compulsion | Consent extracted by threats, or by the economic compulsion of employment, is not free |
Mistake known to the defendant | Where the defendant knows the plaintiff is consenting under a misapprehension, he cannot rely on the consent |
Incapacity | A minor or a person of unsound mind may be unable to give an effective consent to the particular risk |
Consent to an unlawful act | Consent to an act the law forbids for the protection of the person consenting is ineffective |
A statutory duty | A duty imposed by statute for the plaintiff's protection cannot be waived by his consent |
4. Rescue Cases: The Rescuer Is Not Volens
📖 Haynes v. Harwood [1935] 1 KB 146 Facts The defendant's servant left a two horse van unattended in a crowded street. A boy threw a stone at the horses and they bolted. The plaintiff, a police constable on duty in a nearby police station, saw a woman and children in grave danger and ran out to stop the horses. He succeeded and was seriously injured. Held The defendants were liable. Volenti non fit injuria did not apply. Ratio A person who, in an emergency created by the defendant's negligence, intervenes to save life or property, under a legal or moral duty to do so, does not freely and voluntarily consent to the risk. His act is not a free exercise of choice but a response the defendant's own wrongdoing invited. Nor does the rescue break the chain of causation. The principle is often put as: danger invites rescue. |
- The rule protects both the professional and the lay rescuer, though a professional rescuer such as a fireman is expected to take the precautions his training provides.
- The rescue must not be utterly foolhardy. A wholly unreasonable intervention may be treated as a novus actus, or as contributory negligence.
- It applies to the rescue of property as well as of persons, though the courts will weigh the value of the property against the risk taken.
- The companion principle is that the rescue is not a novus actus interveniens, so the defendant remains liable for the rescuer's injuries as well as the victim's.
5. Volenti in Employment
- The defence is rarely available. Smith v. Baker settled that a workman who continues at his work knowing of a danger is not on that account volens.
- The reason is economic compulsion. The choice between running the risk and losing one's employment is not a free choice, and consent extracted by that pressure is not voluntary.
- It may succeed where the workman freely and deliberately courts a danger outside the scope of his duties, with a genuine alternative available to him.
- It never answers a breach of statutory duty imposed for the protection of workmen. The statute would be worthless if it could be contracted out of.
- The employer's duty is personal and non delegable, so the defence cannot be built on the plaintiff's acceptance of an unsafe system provided by somebody else.
6. Volenti in Sports
- Players and spectators accept the risks ordinarily incidental to the game. A boxer consents to blows struck within the rules; a footballer to the ordinary contact of the sport.
- Hall v. Brooklands Auto Racing Club [1933] 1 KB 205 is the standard authority. A spectator at a motor race was injured when two cars collided and one left the track. The club was not liable: a spectator takes the risk of such damage as is inherent in the sport and could not reasonably have been anticipated to be greater.
- Wooldridge v. Sumner [1963] 2 QB 43 refined it. A photographer at a horse show was injured by a horse ridden too fast round a bend. The rider was not liable: a spectator accepts the risk of an error of judgment made in the heat of competition, though not of a reckless disregard of his safety.
- Consent does not extend to a deliberate foul, nor to conduct in reckless disregard of the rules, nor to a danger in the premises or the arrangements themselves.
- The organiser owes a separate duty in respect of the safety of the ground, the barriers and the arrangements, and volenti does not answer a failure in that.
7. Volenti in Medical Treatment
- Consent is what makes lawful what would otherwise be a battery. A surgical incision without consent is a trespass to the person, however skilfully performed and however beneficial.
- The consent must be informed, extending to the nature and purpose of the procedure and to its material risks. A consent obtained without disclosure of a material risk may found a claim in negligence for failure to warn.
- Consent to one procedure is not consent to another. A surgeon who, during an authorised operation, performs a different one for which no consent was given acts without justification, unless an emergency arises.
- In an emergency, necessity supplies the justification where the patient is unable to consent and the treatment cannot be postponed.
- The consent of a person other than the patient is effective only where the law makes it so, as with a minor or a person unable to decide for himself.
8. The Limits of the Defence
⚠ Where volenti simply does not run The defence has no application to a rescuer, nor to a person acting under a legal or moral duty in an emergency the defendant created. It does not answer a breach of a statutory duty imposed for the plaintiff's protection, because the statute cannot be waived by the person it protects. It does not extend to the defendant's negligence merely because the plaintiff consented to the act: consent to an operation is not consent to a careless one. It cannot be founded on the plaintiff's continuing in employment, which Smith v. Baker settled. And it is displaced where the consent was obtained by fraud or compulsion, or given by a person without capacity. What is left is a narrow defence, applicable mainly where the plaintiff freely and deliberately accepted a known risk with a real alternative open to him. |
9. The Position Stated Shortly
1. Volenti non fit injuria means that to one who consents, no injury is done.
2. The defendant must prove that the plaintiff knew of the risk, agreed to run it, and that the agreement was free and voluntary.
3. Knowledge alone is never enough: the maxim is volenti and not scienti non fit injuria.
4. Smith v. Baker holds that a workman who knew of a danger and protested was not volens, the question being whether he accepted the legal risk.
5. Consent obtained by fraud or compulsion is no consent, and a statutory duty imposed for the plaintiff's protection cannot be waived.
6. Haynes v. Harwood holds that a rescuer acting in an emergency created by the defendant does not freely consent to the risk.
7. In employment the defence is rarely available, because the choice between the risk and the job is not a free one.
8. In sports, players and spectators accept the risks ordinarily incidental to the game, but not a deliberate foul or a reckless disregard of the rules.
9. In medical treatment, informed consent makes lawful what would otherwise be a battery, and consent to one procedure is not consent to another.
10. Consent to the act is not consent to its negligent performance, and the burden of establishing the defence lies throughout on the defendant.